Lose telegraphie m



April 1o, 192s. 1,665,632

M. LOCK RADIO SIGNALING SYSTEM Filed NOV. 3, 1925 INVENTOR ICHAE LOCK TORNEY Patented Apr. l0, i928.

UNITED stares PATENT OFFICE.

MICHAEL LOCK, OF BERLIN, GERMANY, ASSIGNOR TOGESELLSGHAFT FR DBAHT- LOSE TELEG'RAPHIE M. B. H. HALLESCHES, GF BERLINyGERMANY.

RADO SGNALING SYSTEM'.

Application led November 3, 1925, Serial' No. 66,50%,l and in Germany November 5, 1924.

This invention relates to what is known as a duplex signaling system wherein the antenna circuit is common to the transmit ter and receiver. The object of the invention is to minimize the 'voltage disturbances in the receiver' whichv arise from the transmitter.

Another object of my invention is to employes few high potential eondensers as possible.

A further object of my invention is to ol tain radio telephony communication by dupleX system in as simple a manner as possible.

The above objects are accomplished and the advantages secured by my invention will be understood by a brief explanation of the operation of my deviceyreference being made to the drawing wherein the figure is a circuit arrangement of the system. N Referring to the gure the numeral i rep resents an antenna, 2 acondenseri 3 an inductance, 4 a transmitting; circuit, 5 a high frequency alternator for the transmitting cir cuit, 6 is a coil consisting` of a limited number of turns in parallel with an inductance 7 8 is a resonant circuit tuned to the incoming wave and coupled inductively to the coil 6, 9 is a radio receiving circuit. l() is a ground.

In the duplex system it is of special importance that the transmitting and the receiving apparatus should be mounted in as close proximity as possible and that they should be connected to one and the same aerial. This desideratum is particularly true of radio telephony over high potential lines. In this connection it is, very dimcult, to provide more than one aerial contiguous to the high tension wires in instances where the coupling between the high frequency apparatus and the high tension lines consists of an aerial system. The same situation holds true when high potential condensers are employed as the coupling elements. The aim evidently then should be to use as few high potential condensers as practicable and these condensers should be used for both transmission and reception.

lt is very important that the antenna connections in radio telephony be so made as to reduce to a minimum the interference occasioned by transmitted waves of low frequency in the receiving apparatus.

The method ot using but one coupling wire for both reception and transmission has been made use of in the art wherethe transmitter and receiver` were arranged in series and where a circuit branch was disposed in parallel tothe receiver having a blocking action, with reference to incoming oscillations, while possessing a short circuiting eti-ect with regard to the sending wave. The blocking was accomplished by what is known as a stopper or blocking cir cuit and the short circuit effect was realized by means of the series arrangement of an inipedance which compensated the impedance of the blocking circuit for the transmission frequency. i

While the above method in principle solves the problem it involved the disadvantages that the magnitude of the two systems of waves has to be comparatively disproportionate in order that the short circuiting shunt at the receiver might not ofl'er an unduly high ohmic resistance for the sending current whereby the effect aimed at would have been impaired. Another difhculty arose in that the resonance adjustments thus obtained were relativelyv sharp with the reu sult that ease of operation and manipulation was lost. Also slight changes in the sending frequency rendered the system unstable.

The present invention provides a parallel branch for the receiving apparatus consisting of a. coil 6 of a limited number of turns with whichV a tuned or vresonance circuit 8 tuned to the Aii'icoming wave is coupled in ductively. This arrangement has exceptionally valuable characteristics. The disturbing potential impacts from the transmitter are deprived of their inductive actions upon the receiver since the latter is completely short circuited to all save receiving frequency. Slight changes therefore in the transmitting wave are unnoticeable so far as the receiver is concerned.

Some slight attenuation of the receiving oscillations is encountered by reason of the shorting effect of the shunt. By the selec tion of variable coupling between the coupled circuit 8 and the shorting shunt 6, it is possible by the transfer of capactive resistance, to compensate for whateverundue seltinductance for the transmittingfrequency there may be in the short circuiting shunt.

It will be clear that the general principles herein disclosed may be embodied in many other organizations different from those illustrated without departing from the spirit of the invention as set forth in the hereinafter claims.

Vhat is claimed is l. ln a duplex radio signaling system, an aerial, a source of high Jfrequency oscillations and a receiving circuit, means to conw nect the source of high frequency oscillations and the receiving circuit in series with the aerial, a coil in parallel to the aerial coinprising a few turns, and a circuit tuned to the incoming Wave coupled to sait` coil.

2. ln a duplex radio signaling system, a source oi electrical oscillations inductively coupled to an antei'ina, an inductance in series with the antenna, receiving means for incoming oscillations coupled to said inductance, a circuit in parallel to the inductance and a tuned circuit non-conductively coupled to said circuit.

3. in duplex radio signaling system in combination, an antenna circuit, a source of high frequency oscillations, a receiving circuit, means to couple the source ot high trequcncy oscillations and receiving circuit to the antenna circuit. to shunt transmitting voltage disturbances from the receiving circuit, said shunting means consisting ot a coil connected to the antenna and, a resonance circuit tuned to the incoming Wave coupled to said coil.

4t. ln a duplex radio signaling system, an antenna, a transmitter of electrical oscillations, a plurality of inductances in series With the antenna, anindicating circuit inmesses ductively coupled to one ot the inductances, means coupling the transmitter and other inductance, a coil connected to the antenna, a tuned circuit inductively coupled to the coil and resonant with incoming oscillations and means to tune the indicating circuit to resonance with incoming oscillations Wherehy disturbing transmitting voltages are miniinized.

5. ln a duplex radio signaling system, a circuit adapted to receive incoming oscillations. a source ot high frequency oscillations coupled to said circuit, an indicating circuit coupled to said circuit, means to tune the indicating circuit to resonance with incomii'ig oscillations, means to short circuit the traiismitting oscillations, said short circuiting means comprising a circuit consisting ot an inductance, and an independent tuned circuit inductivel7 coupled to the short circuiting means.

6. ln a duplex radio signaling system, a source of transmitting electrical oscillations, an indicating circuit resonant to incoming oscillations, an aerial common to the source ot electrical oscillations and to the indicating circuitn a plurality of inductances in series with the antenna, a coil circuit in parallel with one ot the inductances, a second coil inductively coupled to the coil circuit and means to tune the second coil to resonance with incoming oscillations.

MICHAEL LOCK. 

